Refrigerated display case



Allg'. 14, 1945. W W BLAlR 2,382,599

REFRIGERATED DISPLAY CASE Original Filed Aug. 19, 1942 5 Sheets-Sheet 1 Afro/wr Aug. 14, 1945.

w. w. BLAIR 2,382,599

REFRIGERATED DISPLAY CASE 5 Sheets-Sheet 2 Original Filed Aug. 19, 1942 /NV-NTOR:

ArTOR/VEK Aug- 14, 1945 w. w. BLAIR 2,382,599

REFRIGERATED DISPLAY CASE Original Filed Aug. 19, 1942 3 Sheets-Sheet 5 a 85" :l 79 796 f6 Patented Aug. 14, 1945 REFRIGERATED DISPLAY CASE vWilliam Wallace Blair, Lakewood, Ohio Continuation of application Serial No. 455,307, August 19, 1942. This application July 20, 1944,

Serial No. 545,827

12 Claims.

This invention relates to artificially cooled display cases suitable for thedisplay of perishable food products on sale; and the present application is a continuation of my application Serial No. 455,307, filed August 19, 1942.

I'he prime object ofthe invention is the provision of a refrigerated display case particularly suited for the effective display and effective refrigeration of frozen foods on sale.

More specifically, it is an object of the invention to provide a display case for frozen foods in which the transparent inspection panels or windows of the case can be maintained substantially free from clouding by moisture condensed on the interior thereof.

A further object of the invention is to provide a display case of the character last noted which is constructed to insure both the effective display of the food products and easy access to said products without causing a clouding of the interior of the transparent inspection panels of the case, so that the opening of the case from time to time for the sale of foods therefrom does not interfere -with the effective display of the products.

Another object of the invention is the provision ofa display case ofthe character referred to which provides convenient access for cleaning the interior of the case and maintaining it in a sanitary condition.

Still another object of the invention is the provision of a display case of the character referred to that is susceptible of production at moderate cost.

Other objects of the invention more or less incidental or ancillary to those above enumerated will appear from the following description of preferred forms of construction illustrated in the accompanying drawings.

With the foregoing objects in view, the invention, inits broader aspects, consists essentially in the provision of a display case in whichthe interior chamber and the display space of the case are formed by a novel wall structure comprising a bottom chamber wall effectively heat insulated, a front chamber wall that rises from the front part of the bottom wall and has a transparent section disposed to permit easy visual inspection of products in the display case, a barrier Wall extending longitudinally of the case with its bottom boundary located well above the upper face of the bottom wall, and a rear wall (Cl. (i2-89.5)

to the rear of the barrier wall with substantially Y all parts thereof above the lower boundary of A the said barrier wall, and in the provision of cooling meansfor the chamber of the case comprising mechanically refrigerated heat-absorbing means chiefly disposed in the lower part of the case chamber and serving to at least partially. bound the display space and to cool the products displayed. The rear wall section of the case is preferably carried upward so as to enclose the barrier wall, and whenthe latter does constitute an interior wall it can be constructed in various ways, as will later be explained. Whether the barrier Vwall constitutes an interior or an exterior wall section. a space is provided between the lower` boundary of the barrier wall and the rear wall through which when the access door is open a `person can reach to the front part of the display space of the case to introduce or remove the displayed products. The means for cooling the case may include heat-absorbing elements disposed above the products in the lower part of the display space but cooling means so disposed is not very effective for low temperature cooling and it is preferable to use only the bottom cooling means which absorbs heat from the products on display by ,direct conduction aswell as by radiation from the food products. With the parts of the case constructed, combined and arranged as stated effective low temperature cooling suitable for frozen foods may be had and the barrier wall, when the case is opened, effectively opposes movement of warm, moistureladen exterior air to the inner surfaces of the transparent wall section so that clouding of said section by `condensation of moisture' thereon is minimized and relatively frequent opening of the case for sale oi goods therefrom is entirely feasible Without interfering with eii'ective display of the goods.

For a more detailed explanation of the invention reference is now made to the accompanying drawings.

Fig. 1 is a front elevation of a display case embodying the invention, some ofthe structure being broken away to permit illustration on a larger scale and some of the parts being shown in section. i

Fig. 2 is a section on the line 2-2'of Fig. 1.

Fig. 3 is a front elevation of a display case generally similar to that of Figs. 1 and 2 but differing from the latter in certain respects.

Fig. 4 is a section on the line 4-4 of Fig. 3.

Fig. 5 is afrontielevation of still another modification of the case shownin Figs. 1 and 2.

by a longitudinally-extending strip I1 Fig.` 6 is a section on the line 6-6 of Fig. 5.

Referring first to Figs. 1 and 2, the casing structure comprises a supporting frame part having upright members I, I and horizontal members 2, 2 and 3, 3, the frame structure being designed to rest upon the floor or a floor level base. portion of the superstructure containing the display chamber of the case are covered by metal sheets l and on the front and rear sides, respectively, and by metal sheets 8 on the ends of the structure, such metal sheets being given any desired finish.

The display chamber of the case has enclosing walls comprising a bottom wall made up of boards 1 and thick heat-insulating material slabs 8 of cork or the like.4 'Ihe chamberhas a iront wall structure designated as an entirety by the numeral 9 and comprising a low vertical portion I0 and an upwardly and rearwardly inclined panel I I made up of a frame I I'L and a plurality of glass panes IIb, the space between the glass panes affording dead air heat insulation. Any approved form of transparent panel construction with any suitable number of layers of glass may be employed for'the panel II. The rear wall of the display chamber which is designated as an entirety by the numeral I2 comprises a vertical part I2- and an access panel I4 comprising a iframe structure I4* and sliding doors Il, the panel Il preferably being disposed to slant forwardly from the upright wall section I3 to the top wall section I5 which connects the panels Il and Il.

The end walls of the display chamber are formed by the metal sheets 6 and heat-insulating layers i* supported on thevbottom wall 1, 8.

Within the display chamber is a barrier wall I8 which, inthe construction shown in Fiss. l and 2, is in the form of a curtain wall composed of a sheet of flexible material secured at its upper edge that is attached by screws to the top wall I5 of the case. The curtain wall I6 is preferably formed of suitable iiexible material such as sheet rubber, rubberized fabric or fabric which has been given a water-repellent treatment.

The curtain wall I6, as indicated in Fis. l, ex-

The supporting frame-structure and a' plates and are suitable for supporting food products or other materials to be cooled.

The expansion coil I9 has its inlet end connected with a liquid refrigerant supply conduit 2l which may be connected with a refrigerant receiver and motor-driven compressor (not shown) /of a closed refrigeration circuit, in well known manner. The outlet end of the expansion coil is connected with a suction return conduit 22 which may be connected with the suction inlet of such compressor. The conduit 2I is provided with a thermostatic expansion valve 23 having its thermostatic bulb 24 disposed, in known fashion, .in ntct with the suction conduit 22 as shown in In the use of the case for the display of frozen lfoods, the control devices of the refrlgerating tends substantially the full length of the display chamber of the case and is disposedl so that its lower edge or boundary is at least as low as the lower side ofthe opening controlled by the doors IIb. Also a space is left between the lower boundary of the curtain wall I6 and the rear wall of the display chamber, thus forming at I8 a substany tially horizontal open space which is in effect controlled by doors I4b and through which the display space in front of the wall I8 may be reached l when one of the doors Hb is opened.

Cooling means for the display chamber of the case is provided in the form of a refrigerant expension coil I9, the tubing of the coil being looped back and forth from one end of the case to the other to form a horizontal element overlying the bottom wall of heat-insulating material 8 and extending upward adjacent the rear wall section I3, although the upright loops of the coil adjacent wall I3 may, if desired, be omitted. The coil I9 is preferably hermetically enclosed in a sheet metal casing 20 which, when the interior of the casing is exhausted. is held in close metal-tometal contact withthe tubing of the coil. Refrigerant expansion elements of this character are available on the market and are of well known construction.. They are commonly known as cold mechanism' are set or adjustedto maintain the expansion coil I9 at a temperature suitable for such frozen foods, that is," amply low to prevent the foods from softening. Usually a temperature of 0 F. or lower is desirable. The food products, such as fruits, vegetables, meats and the like, are suitably arranged for display upon the cold plate and such arrangement can be made easily and conveniently by introducing the products through the access openings controlled by doors I4. When this is done the lower part of the curtain wall It is free to move forward so that the front part of the display space of the case is readily reached and products of large size are readily introduced or removed. In the operation of the case, heat is extracted from the food products, in part at least by direct conduction to the cold plate or refrigerant coil and the air surrounding the food products up to the level of the access openings controlled by the doors Ilb is effectively maintained at a suitably low temperature, the temperature of the air in the display compartment being increasingly higher at successively higher levels up to the top of said chamber.

When food products are introduced or removed from the case the curtain wall I8 eilectively prevents any substantial movement of exterior air forward past saidI wall because the air in the case below the level of the access opening is at a much lower temperature and therefore heavier than the exterior air that may enter the case chamber when the door Ilb is opened; and, since the lower part of the curtain wall I-B extends downward to or below the level of the access opening, the incoming warm air is effectively stopped by the curtain and the layer of cold air below it. Consequently the exterior air, which may and usually does carry considerable moisture, is effectively prevented from moving forward into contact with th'e inner side of the glazed panel II and condensation of moisture on the inner side of said panel is thus prevented and clear vision through the panel is maintained. 'I'he described eiect of the curtain wall I6 is indicated by the fact that in the operation of the display case the said wall may be heavily covered on its rear side with condensed moisture while its front side is entirely dry. It will, of course, be apparent that the curtain wall I6, in addition to opposing entrance of exterior air into contact with the inner side of the glass inspection panel, at the same time helps to minimize escape of cold air from the case.

The modified form of cabinet shown in Figs. 3 and 4 is in many respects the same as the cabinet above described and in these similar respects need not be described in detail. Suillce it to state that in the second form of construction the supporting framework comprises upright members Il and horizontal members 32, 33. Exterior sheet metal covering parts 34, 35 and 36 enclose the said framework and a portion of the superstructure. The latter comprises bottom wall parts 31 and 38 for the display chamber, front wall structure 39 having insulation section 48 and rearwardly inclined transparentinspectionv panel 4|, rear wall structure 42 having upright insulation section 43 and forwardly inclined frame section 44 with access opening 44 controlled by doors 44", and Walle insulation sections 36, 36, and, finally, top wall section 45. Within the display chamber is disposed a curtain or barrier wall designated as an entirety by the numeral ,46 ,and shown divided into two independent sections 41 and 48. The curtain wall sections 41 and 48 are formed of sheet metal and are pivotally supported from the top wall 45 by means of hinge plates 49, 49 attached to the top wall 45 and having hooks 49, 49 which are engaged by apertures 41 and 48 in the sections 41 and 48. Thus mounted the ycurtain wall sections are free to swing forward or backward and can very easily be lifted off their supporting hooks when it is desired to clean the interior of the display chamber.

Asfrm the case of the curtain wall'ls of the first described case, the modified curtain wall construction at either end is disposed closely adjacent the end walls of the case. In order similarly to minimize movement vof air past the mutually adjacent ends of the curtain sections 41 and 48 a depending curtain Wall 50 at right angles to the wall sections 41 and 48 is attached to the top wall 45 of the`case so as to depend between said adjacent ends of said sections.

The curtain wall sections 41 and 48 have their lower edge portions bent rearward to. formdrain troughs 41b and 48" which serve to catch moisture that condenses on the rear surface of the wall sections, the troughs being inclined somewhat toward the ends of the case, where the moisture is deposited.

The curtain wall sections 41 and 48 may be made of any suitable material but I prefer to form them of corrosion-resistant metal and to provide mirror surfaces on their front sides. This can conveniently be done by finishing the front faces 'of the sections with a high polish.,

The display chamber of the case in the modiiied construction is cooled by a plain flat cold plate of the character shown in Figs. 1 and 2 but without a vertical section at the back, and diiiering further in that the refrigerant expansion coil 52 of the plate is connected in series with a coil 53 disposed in the top part ofthe display chamber. With this construction 'a refrigerant inlet conduit 5'4 provided with a thermostatic expansion valve 55 is connected to the inlet end of the coil 52 and a suction return conduit 56 is connected with the outlet end of the coil 53.

( 3 case, facilitates the cleaning of the interior of the case. Also the deposit of condensed moisture at two points in the display chamber makes removal of such condensed moisture somewhat easier. .v

The display case shown in Figs. 5 and 6 differs from that shown in Figs. 1 and 2 chiey with respect to its cooling means, although it also is distinguished by a deeperl display space than the first described case and by the fact that the walls of the lower part of the display space have a lining of sheet metal.

As in the Yfirst construction the .case has a supporting framework comprising upright members 6| and horizontal members 82, 63. Exterior sheet metal covering parts 64, 65 and 66 enclose the said framework and a portion of the superstructure. K The latter comprises bottom wall parts 61 and 68 for the display chamber, a front wall structure 69 having an insulation section 16 and a rearwardly inclined transparent inspection panel 1|, rea-r wall structure 12 having upright insulation section 13 and forwardly inclined section 14 with access opening 14EL controlled by doors 14h, end wall insulation sections 15, 15, and a top wall section 16. The front wall section 10, rear wall section 13, the lower parts of the end wall sections 15, 15 and the .bottom wall Section 68, are provided with a lining 11 of suitable sheet metals .A curtain or barrier wall 18 of the same character as the wall I6 of the first described construction is suitably suspended from the top wall 16, in the food chamber of the case and extends from one end to the other of the chamber.

The chamber of this third form of case is cooled by two elements 19 and 88 of the cold plate type already described, the element 19 having an expansion coil 19a and an enclosing metal shell 19b and the element 80 similarly having an ex- Dansion coil 80 and shell 801i'.v These elements 18 and 80 extend substantially the full length of the display chamber and are arranged on edge. the element 19 being secured adjacent and in contact with the metal lining of the front wall section 18 while element 80 is similarly secured in relation to the rear wall section 13. The coils I, y 1!!n and 80 are connected in series-by pipe 8| It is believed that the functioning of the modifled form of construction will be apparent from the description of the case shown in Figs. 1 and 2. but it may be observed that in the use of the modified form of case the curtain wall sections 41 are free to swing forward on their supports to facilitate removal of the food products from the display case. It will also be apparent that the mirror surfaces of the curtain wall, by reflecting images of the products in the case, will facilitate and amplify the display secured.

It will also be clear that the ease with which the curtain sections 41 and 48 can be detached from their supports and rested upon the bottom wall of the case or completely removed from the (at the right end of the case in Fig. 5) and refrigerant inlet conduit 82 fitted with a thermostatic expansion valve 83 is connected to the inlet end of coil 19B. A suction return conduit 84 for vaporized refrigerant is connected with the outlet end of the coil 86, the thermostatic bulb 83= of valve 83 being disposed in thermal contact with conduit 84.

The operation of this last-described display case will be apparent from the description of the case shown in Figs. 1 and 2 but it may be pointed out that while the refrigerant cooling means does not extend across the bottom of the display chamber the disposition of the cold plates at both front and rear of the food space provides extensive surfaces to be contacted` directly by the food products and affords adequate cooling capacity. Furthermore, the metal lining 11 with which the food is in contact at the bottom and ends of the display space serves to conduct a considerable amount of heat from the food to the cold plates. Of course the metal lining and the cold plates absorb heat by radiation from the food and both the lining and cold plates absorb heat by air conduction.

While the metal lining is shown only in connection with the case last described, it is obvious that aeanbeusedamnariymbouicrrne other eues,

disclosed.- Insofar as the cooling is concerned it will be observed that in each of the three forms of construction disclosed the heat-absorbing means is chiefly disposed in the lower part of the display space of the case and serves to at least vention as it is defined in the appended claims.

What is claimed is:

l. In a refrigerated display case, the combination of a wall structure and refrigeratingI means defining an enclosed chamber providing a display space suitable for products to be displayed therein and dispensed therefrom, the refrigerating means being chiefly disposed in the lower part of the said chamber and serving to at least partially bound the display space thereof and said wall structure comprising a heat insulating botwm chamber wall, a front chamber wall rising from said bottom wall and having a transparent section, a barrier wall extending 'substantially from one end of the case to the opposite end thereof and having its bottom boundary above the bottom of the display space, and a rear wall having a section extending upward from the rear part of the bottom wall and having a movable door section controlling an opening which as an entirety is disposed to the rear of said barrier wall and' at least as high approximately as the lower boundary of said barrier wall, the refrigerating means, the transparent section of the front chamber wall and the barrier wall being disposed in such relation to each other as to render substantially the entire bottom of the chamber visible through said transparent section, whereby when the door is open, access is afforded through the space between the rear wall section and vthe lower part of the barrier wall to the display space of the case for the insertion therein and dispensing therefrom of 'said products while the barrier wall forms a barrier against movement of exterior air to the inner side of thetransparent section of the front wall of the case.

2. A refrigerated display case as claimed in claim 1, in which the refrigerating means comprises an element constructed and arranged to form the bottom of the display space of the case.

3. A refrigerated display case as claimed' in ,facilitate reaching the front part of the display Y space of the case through the door-controlled access opening thereof.

5. A refrigerated display case as claimed in claim l, in which vthe barrier wall is in the form of a curtain wall disposed within the chamber of the case and has at least its lower portion movable forward and backward to facilitate reachinl the front part of the display space of the case tlfirough the door-controlled access opening there- 0 6. A refrigerated display case as claim 1, in which the barrier wall is in the form of a flexible curtain suspended from its upper edge within the chamber of the case.

'1. A refrigerated display case as claimed in c1aim'1,in which the barrier wall is relatively rigid and pivotally suspended from its upper edge within the chamber of the case.

8. A refrigerated display case as claimed in claim 1, in which the barrier wall is in the form of a plurality of substantially rigid sections arranged end to end and pivotally suspended from their upper edges within the chamber ofthe case.

9. A refrigerated display case as claimed'in claim 1, in which the barrier wall is disposed within the chamber of the case and is provided on its rear side with a drain trough for the collection of moisture condensed on its rear surface.

10. A refrigerated display case as claimed in claim 1, in which the barrier wall has a mirror surface on its front side.

11. A refrigerated display case as claimed in claim 1, in which the transparent front wall section is inclined rearward and upward to partially overlie the bottom wall of the case chamber and facilitate inspection of the display space.

12. A refrigerated display case as claimed in claim 1, in which the case is constructed to rest upon the floor and has the bottom wall of the display chamber thereof disposed well above the oor level and the front transparent wall section inclined rearward and upward to partially overlie the said bottom wall, whereby inspection of the interior of the display chamber through the transparent wall is facilitated.

WILLIAM WALLACE BLAIR.

claimed in n 

